Anthropic trained Claude on over 7 million pirated books from LibGen and Pirate Library Mirror
Aug 1, 2024A class action lawsuit (Bartz v. Anthropic) filed in August 2024 alleged Anthropic used over 7 million digital copies of copyrighted books acquired from pirating sites Library Genesis and Pirate Library Mirror to train its Claude language models. In June 2025, Judge Alsup ruled that while using legally acquired books for AI training was fair use, training on pirated copies was not protected.